What might an adult have fewer teeth than this?

An adult may have fewer teeth than a child if they have lost teeth due to:

- Gum disease: This is the leading cause of tooth loss in adults.

- Tooth decay: This is another common cause of tooth loss.

- Injury: Teeth can be knocked out or damaged in accidents or sports injuries.

- Medical conditions: Some medical conditions, such as diabetes, can increase the risk of tooth loss.

- Medications: Some medications can cause side effects that can damage the teeth.

- Genetics: Some people are more likely to lose teeth than others due to their genetics.

It is important to see a dentist regularly to prevent and treat tooth loss.